Zinc metal negative electrode, secondary battery, and electric device

Abstract

The application discloses a zinc metal negative electrode, a secondary battery and an electric device. The zinc metal negative electrode comprises a zinc metal negative electrode base body and a modification layer arranged on the surface of the zinc metal negative electrode base body, and the modification layer comprises nitrogen-containing carbon material. The modification layer containing the nitrogen-containing carbon material can isolate the direct contact between the zinc metal negative electrode base body and the electrolyte, inhibit the electrolytic hydrogen evolution reaction on the negative electrode surface, relieve the local corrosion of the negative electrode, and in addition, the nitrogen-containing carbon material can guide the transmission path of zinc ions, so that the electric field distribution on the negative electrode surface is uniform, the growth of zinc dendrites is inhibited, and the cycle stability and cycle life of the battery are improved.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to zinc metal anodes, secondary batteries, and electrical equipment. Background Technology

[0002] The commercialization of lithium-ion batteries has made a significant contribution to energy storage, but it has also brought some problems, such as high cost and low safety. Compared with lithium-ion batteries, aqueous metal-ion batteries, especially zinc-ion batteries (ZIBs), have a higher specific capacity (5855 Ah / L for the zinc anode). -1 The lithium anode is 2061 Ah L -1 With lower material and assembly costs, as well as a safer operating system, zinc-ion batteries can serve as an alternative to lithium-ion batteries.

[0003] However, existing zinc-ion batteries still have the following problems in application:

[0004] (1)Zn 2+ Free water molecules within the first solvation layer readily undergo electrolytic hydrogen deposition near the zinc anode surface, causing localized corrosion of the zinc metal and increasing the pH of the electrolyte environment. This leads to anion reactions with Zn in the electrolyte. 2+ It has a strong coupling effect and is prone to forming various basic byproducts (electronic insulation) in solution environments with gradually increasing pH, thereby causing the deterioration of the cycle performance and rate performance of zinc-ion batteries.

[0005] (2) As the zinc anode / electrolyte process continues to deposit / strip metallic zinc, the electric field distribution at the zinc anode / electrolyte interface will be uneven, which will easily lead to the growth of zinc dendrites and reduce the cycle stability and cycle life of zinc-ion batteries. Summary of the Invention

[0006] This invention provides a zinc metal anode and its preparation method, aiming to solve the technical problem of poor cycle life in existing zinc metal batteries.

[0007] The zinc metal anode provided by the present invention includes: a zinc metal anode substrate and a modification layer disposed on the surface of the zinc metal anode substrate, wherein the modification layer includes a nitrogen-containing carbon material.

[0008] Furthermore, the nitrogen-containing carbon material includes graphitic nitrogen, pyridine nitrogen, and pyrrole nitrogen.

[0009] Furthermore, the thickness H1 of the modified layer is 200nm to 2000nm.

[0010] Furthermore, the thickness H2 of the zinc metal anode substrate is 0.5 mm to 5 mm.

[0011] Further, the molar ratio of the graphite nitrogen, the pyridine nitrogen and the pyrrole nitrogen in the modification layer is (35-65):(15-40):(20-30).

[0012] Further, the nitrogen atom accounts for 0.3%-5% of all elements in the nitrogen-containing carbon material.

[0013] Further, the root mean square roughness of the modification layer is R q 1.10-2.00, and the arithmetic mean roughness R a

[0014] The application further provides a preparation method of the zinc metal negative electrode.

[0015] The zinc metal negative electrode substrate is placed in a chemical vapor deposition device;

[0016] The carbon-containing gas, the nitrogen-containing gas and hydrogen are sequentially introduced into the chemical vapor deposition device to obtain the zinc metal negative electrode.

[0017] Further, the preparation method is as follows:

[0018] 1) The zinc sheet is placed in a plasma enhanced chemical vapor deposition system (PECVD), and the vacuum degree of the system is controlled in a first pressure range;

[0019] 2) The carbon-containing gas is introduced, the vacuum degree in the system is maintained in a second pressure range, the plasma system is turned on, the first output power is set and the circuit reflected power is adjusted to a first value, the plasma system is turned off after running for a first time, and the introduction of the carbon-containing gas is stopped;

[0020] 3) The nitrogen-containing gas and H2 are introduced, the vacuum degree in the system is maintained in a third pressure range, the plasma system is turned on, the second output power is set and the circuit reflected power is adjusted to a second value, the PECVD system is turned off after running for a second time, the introduction of the nitrogen-containing gas and H2 is stopped, and a zinc sheet coated with nitrogen-doped carbon, i.e. a zinc metal negative electrode, is obtained;

[0021] In the step 1) of the method, the first pressure range is 1x10 -3 Pa or below;

[0022] In the step 2) of the method, the carbon-containing gas includes one or more of methane, acetylene and propylene, and preferably is methane;

[0023] The carbon-containing gas is introduced at a first flow rate, and the first flow rate is 10-25 sccm;

[0024] The second pressure range is 0.1-10 Pa;

[0025] ​The first output power comprises 250-350 W;

[0026] The first value is 0-2 W;

[0027] The first time comprises 50-70 min;

[0028] In the step 3) of the method, the nitrogen-containing gas comprises one or both of nitrogen and ammonia;

[0029] The nitrogen-containing gas is introduced at a second flow rate,

[0030] The ratio of the second flow rate to the second output power is 10-30 sccm: 200-1000 W;

[0031] H2 is introduced at a third flow rate,

[0032] The third flow rate is 10-25 sccm;

[0033] The third pressure range is 2x10 -1 -2x10 Pa, preferably 0.5-10 Pa;

[0034] The second output power comprises 250-350 W;

[0035] The first value is 0-10 W;

[0036] The second time comprises 5-20 min, preferably 5-15 min, and more preferably 10 min.

[0037] The method further comprises the operation of cleaning the zinc sheet before the step 1).

[0038] The cleaning can specifically be that the zinc sheet is sequentially placed in acetone, deionized water, dilute hydrochloric acid, deionized water, and ethanol for cleaning; and then the zinc sheet after the above cleaning is placed in a vacuum oven at 45-60°C for drying for 4-5 h. In some embodiments, the cleaning comprises ultrasonic cleaning, and the time for each cleaning is 1-3 min, for example, the zinc sheet is placed in acetone for cleaning for 2 min, taken out, placed in deionized water for cleaning for 2 min, taken out, placed in dilute hydrochloric acid for cleaning for 2 min, and then sequentially placed in deionized water and ethanol for cleaning.

[0039] The application further provides a secondary battery comprising the zinc metal negative electrode.

[0040] The application further provides an electric device comprising the secondary battery as a power supply of the electric device.

[0041] The application has the following effects:

[0042] 1. The modified layer containing nitrogen-containing carbon material can be grown in situ on the surface of zinc metal negative electrode substrate at room temperature, and the nitrogen-containing carbon material can be adjusted by adjusting the Zn 2+ The transmission rate and path when passing through the zinc metal surface interface, which causes the uniform distribution of the electric field on the negative electrode surface, thereby effectively inhibiting the formation of zinc dendrites on the negative electrode surface.

[0043] 2. The nitrogen-containing carbon material can isolate the direct contact between zinc metal and electrolyte, inhibit the electrolytic hydrogen evolution reaction on the surface of zinc metal, and alleviate the local corrosion of zinc metal, thereby homogenizing the electric field distribution on the surface of zinc metal. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The plasma device used in the present application is shown in the figure, where the left side is the gas inlet end, the right side is the gas outlet end, the gas outlet end is connected to the vacuum pump system, the gas inlet end is connected to the gas and the corresponding flow meter, and the copper wire wound on the glass tube is connected to the radio frequency power supply and the matching device of the radio frequency power supply. The matching device of the radio frequency power supply is used to adjust the circuit reflection power of the radio frequency power supply.

[0045] Figure 2 The charge-discharge cycle diagram of the symmetrical battery using sample 1 prepared by example 1 and sample (S2) of comparative example 2 as two poles is shown in the figure. DETAILED DESCRIPTION

[0046] The present application will be further described in detail below in conjunction with specific embodiments, and the examples given are only for the purpose of illustrating the present application, but not for limiting the scope of the present application. The examples provided below can serve as a guide for further improvement by those skilled in the art, and do not in any way constitute a limitation on the present application.

[0047] The experimental methods in the following examples are all conventional methods, unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained commercially.

[0048] The present application provides a zinc metal negative electrode, which comprises a zinc metal negative electrode substrate and a modified layer provided on the surface of the zinc metal negative electrode substrate, wherein the modified layer comprises a nitrogen-containing carbon material.

[0049] A modified layer with a nitrogen-containing carbon material is grown in situ on the surface of the zinc metal negative electrode substrate, and the nitrogen-containing carbon material can adjust the Zn 2+ The transmission rate when passing through the negative electrode surface, thereby effectively inhibiting the formation of zinc dendrites on the negative electrode surface, and facilitating the improvement of the cycle stability and cycle life of zinc ion battery.

[0050] In the embodiment of the present application, the thickness H1 of the modification layer is 200 nm to 2000 nm; and the thickness H2 of the zinc metal negative electrode substrate is 0.5 mm to 5 mm.

[0051] In some embodiments, the H1 and H2 satisfy the following relationship: 400≤H2 / H1≤4000.

[0052] If the modification layer is too thick, the transmission rate of zinc ions will be reduced, and the transmission effect at the interface will be poor, which is not conducive to the improvement of the cycle stability and cycle life of the zinc ion battery; if the modification layer is too thin, it is easy to be broken down by a large current, losing the protection effect, and at the same time, the corrosion resistance to the electrolyte will be poor, which is also not conducive to the improvement of the cycle stability and cycle life of the zinc ion battery.

[0053] In one embodiment of the present application, the nitrogen element in the nitrogen-containing carbon material is doped in carbon, and in another embodiment, the nitrogen-containing carbon material includes graphite nitrogen, pyridine nitrogen and pyrrole nitrogen. The graphite nitrogen, pyridine nitrogen and pyrrole nitrogen can increase the zinc storage content of the negative electrode, and can also adjust the electron arrangement of the modification layer, better guide the path of zinc ion deintercalation, so that the electric field is more uniformly distributed on the surface of the negative electrode during the cycle charging and discharging process.

[0054] In another embodiment, the molar ratio of the graphite nitrogen, the pyridine nitrogen and the pyrrole nitrogen in the modification layer is (35-65):(15-40):(20-30).

[0055] In some embodiments, in the nitrogen-containing carbon material, the nitrogen atoms account for 0.3% to 5% of all elements, preferably 1.1% to 1.2%. The content of nitrogen can affect the adsorption of zinc ions by the modification layer, and the higher the nitrogen content, the stronger the adsorption capacity of zinc ions, which can reduce the charge transfer impedance at the interface of the electrode surface; and the higher the total content of pyridine nitrogen and pyrrole nitrogen accounts for the total content of the three kinds of nitrogen, the stronger the adsorption of zinc ions, because compared with graphite nitrogen, pyridine nitrogen and pyrrole nitrogen have stronger adsorption of zinc ions, and therefore, it is more conducive to the improvement of the cycle life of the zinc ion battery.

[0056] The application grows a carbon film with nitrogen-containing carbon material on the surface of a zinc sheet by a chemical vapor deposition method, avoids direct contact between the zinc metal negative electrode matrix and the electrolyte, and inhibits uneven distribution of an electric field caused by the electrolytic hydrogen reaction and the deposition of byproducts on the surface of the zinc metal negative electrode matrix; nitrogen is introduced into the carbon film by nitrogen plasma treatment, H2 plasma treatment is simultaneously performed, and the proportion of various types of nitrogen, such as pyridine nitrogen, pyrrole nitrogen, and graphite nitrogen, is controlled by controlling the H2 plasma treatment time, so that the ability of the negative electrode surface to adsorb zinc ions is enhanced; the modification layer on the surface of the zinc metal negative electrode reduces the roughness of the surface of the zinc metal negative electrode and significantly reduces the contact angle between the zinc metal negative electrode and the electrolyte, thereby improving the wettability of the electrolyte to the zinc metal negative electrode, and thus the obtained zinc metal negative electrode can significantly improve the cycle stability and cycle life of a zinc ion battery.

[0057] The application further provides a preparation method of the zinc metal negative electrode, and the method comprises the following steps:

[0058] The zinc metal negative electrode matrix is placed in a chemical vapor deposition device;

[0059] A carbon-containing gas, a nitrogen-containing gas, and hydrogen are sequentially introduced into the chemical vapor deposition device to obtain a zinc metal negative electrode. The chemical vapor deposition device includes any one of a plasma-enhanced chemical vapor deposition device (PECVD), a high-density plasma chemical vapor deposition device (HDP CVD), a microwave plasma chemical vapor deposition device (MPCVD), a microwave electron cyclotron resonance plasma chemical vapor deposition (ECR-MPCVD), an ultrahigh vacuum chemical vapor deposition (UHV / CVD), and a thermal chemical vapor deposition (TCVD). In actual applications, the chemical vapor deposition method is the most widely used technology for depositing various materials in the semiconductor industry, including a wide range of insulating materials, most metal materials, and metal alloy materials. In theory, two or more gaseous raw materials are introduced into a reaction chamber, and then they chemically react with each other to form a new material and deposit on the surface of a wafer. The chemical vapor deposition method is a traditional thin film preparation technology, and the principle is to use gaseous precursors to decompose some components in the gaseous precursors through atomic and molecular chemical reactions to form a thin film on the substrate.

[0060] In some embodiments of the application, the method comprises the following steps:

[0061] 1) The zinc sheet is placed in a plasma-enhanced chemical vapor deposition system (PECVD), and the background vacuum degree of the system is controlled in a first pressure range;

[0062] 2) introducing carbon-containing gas, maintaining the vacuum degree in the system in a second gas pressure range, opening the plasma system, setting a first output power and adjusting the circuit reflected power to a first value, running for a first time, then closing the plasma system, and stopping the introduction of carbon-containing gas;

[0063] 3) introducing nitrogen-containing gas and H2, maintaining the vacuum degree in the system in a third gas pressure range, opening the plasma system, setting a second output power and adjusting the circuit reflected power to a second value, running for a second time, then closing the PECVD system, stopping the introduction of nitrogen-containing gas and H2, and obtaining a zinc metal negative electrode coated with nitrogen-doped carbon.

[0064] In the method of the present application, the proportion of nitrogen atoms is adjusted by adjusting the time of plasma treatment of the carbon film by N2 and H2, which can also effectively control the nitrogen-related properties of the zinc metal surface interface, thereby affecting the adsorption capacity of the carbon film to zinc ions, i.e., controlling the rate of zinc ions in the mass transfer process at the surface interface, thereby achieving the effect of enhancing the cycle stability.

[0065] An embodiment of the present application shows that the effect of introducing N2 and H2 at the same time is better than that of introducing N2 first and then introducing H2 plasma treatment, because H2 can generate some active groups together with N2 under the action of plasma, enhancing the activity of N-related state atoms and ions, to promote the nitrogen doping modification effect.

[0066] The zinc metal negative electrode prepared by the method of the present application has a reduced surface roughness and a significantly reduced contact angle with the electrolyte, which is beneficial to the wetting of the electrolyte.

[0067] In summary, the zinc metal negative electrode of the present application can significantly improve the cycle stability and cycle life of the zinc ion battery.

[0068] The present application will be further explained by specific examples.

[0069] Example 1

[0070] This embodiment provides a zinc metal negative electrode, and the preparation method is as follows:

[0071] Step one, the zinc metal negative electrode substrate (metal zinc sheet is used in this embodiment) with a diameter of 1.5 cm and a thickness of 0.8 mm is ultrasonically cleaned in acetone, deionized water, dilute hydrochloric acid, deionized water and ethanol, each for 2 min, and then dried in a vacuum oven at 45℃ for 4h;

[0072] Step two, the obtained zinc sheet is placed in a PECVD system, and a vacuum pump system is run to maintain the vacuum in the system at 1×10 -3Pa; then CH4(purity 99.999%) was introduced at a flow rate of 16 sccm, the vacuum pump system was adjusted to maintain the pressure in the chamber at 0.1-10 Pa, the plasma generator was turned on, the plasma output power was set to 300 W, the plasma RF system reflected power was adjusted to 0-2 W, the plasma generator was operated for 60 min, the plasma generator was turned off, and the introduction of CH4was stopped;

[0073] Step three, N2(purity 99.999%) was introduced at a flow rate of 16 sccm and H2was introduced at a flow rate of 16 sccm, the vacuum pump system was adjusted to maintain the pressure in the chamber at 0.5-10 Pa, the plasma generator was turned on, the plasma output power was set to 300 W, the plasma RF system reflected power was adjusted to 0-10 W, the plasma generator was operated for 10 min, the plasma generator was turned off, and the introduction of N2and H2was stopped.

[0074] Step four, the PECVD system was turned off, and the zinc sheet was finally taken out, and the obtained zinc metal negative electrode was recorded as sample 1. The characteristics of the zinc metal negative electrode obtained by sample 1 were recorded in Table 1.

[0075] Example 2,

[0076] The difference between this example and example 1 is that the thickness of the zinc metal negative electrode substrate is 0.5 mm, acetylene is used instead of methane in step two, and the rest remains unchanged. The obtained zinc metal negative electrode is recorded as sample 2.

[0077] Example 3,

[0078] The difference between this example and example 1 is that the thickness of the zinc metal negative electrode substrate is 0.7 mm, propylene is used instead of methane in step two, and the rest remains unchanged. The obtained zinc metal negative electrode is recorded as sample 3.

[0079] Example 4,

[0080] The difference between this example and example 1 is that the thickness of the zinc metal negative electrode substrate is 1 mm, ammonia gas (purity 99.999%) is used instead of nitrogen gas in step three, and the rest remains unchanged. The obtained zinc metal negative electrode is recorded as sample 4.

[0081] Example 5,

[0082] The difference between this example and example 1 is that the thickness of the zinc metal negative electrode substrate is 1.5 mm, the time for operating the plasma generator after introducing N2and H2in step three is adjusted from 10 min to 5 min, and the rest remains unchanged. The obtained sample is named as sample 5.

[0083] Example 6,

[0084] The difference between this example and Example 1 is that the thickness of the zinc metal negative electrode substrate is 3 mm, the time for running the plasma generator after introducing N2 and H2 in step three is adjusted from 10 min to 15 min, and the rest is unchanged. The obtained sample is named as Sample 6.

[0085] Example 7,

[0086] The difference between this example and Example 1 is that the time for running the plasma generator after introducing N2 and H2 in step three is adjusted from 10 min to 20 min, and the rest is unchanged. The obtained sample is named as Sample 7.

[0087] Example 8,

[0088] The difference between this example and Example 1 is that the time for running the plasma generator after introducing CH4 in step two is adjusted from 10 min to 30 min, and the rest is unchanged. The obtained sample is named as Sample 8.

[0089] Example 9,

[0090] The difference between this example and Example 1 is that the time for running the plasma generator after introducing CH4 in step two is adjusted from 10 min to 90 min, and the rest is unchanged. The obtained sample is named as Sample 9.

[0091] Example 10,

[0092] The difference between this example and Example 1 is that the time for running the plasma generator after introducing CH4 in step two is adjusted from 10 min to 180 min, and the rest is unchanged. The obtained sample is named as Sample 10.

[0093] Example 11,

[0094] The difference between this example and Example 1 is that the time for running the plasma generator after introducing CH4 in step two is adjusted from 10 min to 20 min, and the rest is unchanged. The obtained sample is named as Sample 11.

[0095] Example 12,

[0096] The difference between this example and Example 1 is that the time for running the plasma generator after introducing N2 and H2 in step three is adjusted from 10 min to 50 min, and the rest is unchanged. The obtained sample is named as Sample 12.

[0097] Example 13,

[0098] The difference between this example and Example 1 is that the plasma output power in step three is adjusted from 800 W to 900 W, and the rest is unchanged. The obtained sample is named as Sample 13.

[0099] Example 14,

[0100] The running time of the plasma generator in step two was adjusted to 110 min, and the rest remained unchanged. The obtained sample was named sample 14.

[0101] Example 15,

[0102] The running time of the plasma generator in step two was adjusted to 130 min, and the rest remained unchanged. The obtained sample was named sample 15.

[0103] Comparative Example 1,

[0104] The difference between this comparative example and example 1 is that step three was not performed, and the obtained zinc metal negative electrode did not contain nitrogen elements, which was named comparative sample S1.

[0105] Comparative Example 2,

[0106] This comparative example used clean pure zinc metal as the zinc symmetric battery of the two electrodes, which was named comparative sample S2.

[0107] Test Example

[0108] The zinc metal negative electrodes obtained in the above examples and comparative examples were tested to obtain the relevant characteristics of each sample, which are recorded in Table 1. Then, the samples obtained in the above examples and comparative examples were used as the two electrodes, the composition of the electrolyte was 2M ZnSO4 solution, the glass fiber separator, 30 uL of electrolyte was added on both sides of the separator, and a button cell was assembled, and the button cell was tested, and the test data are recorded in Table 1.

[0109] The test methods involved are as follows:

[0110] Test of the thickness of the modification layer: obtained by SEM (scanning electron microscope) measurement of the cross section of the modification layer.

[0111] Ratio of graphite nitrogen, pyridine nitrogen and pyrrole nitrogen: the content and ratio of graphite nitrogen, pyridine nitrogen and pyrrole nitrogen were obtained by XPS (X-ray photoelectron spectroscopy).

[0112] Percentage of nitrogen atoms in all elements: the content of N element was obtained by XPS.

[0113] Roughness: obtained by AFM (atomic force microscope) test.

[0114] Average contact angle drop rate: one drop of 2M ZnSO4 electrolyte was dropped on the surface of the zinc metal negative electrode, and the contact angle A1 was obtained by using a contact angle measuring instrument at 1s, and the contact angle A2 was obtained by continuing to measure after 5 min, and the average contact angle drop rate = (A2-A1) / T, T represents the time of two measurements. Deposition / peeling zinc stability test: 1.0 mAh cm -2the charge-discharge energy density, the charge-discharge capacity of one cycle is 2.0 mAh cm -2 The button cell was subjected to charge-discharge cycle, and when the battery short-circuit failure, the duration of the cycle charge-discharge was recorded.

[0115] Table 1

[0116]

[0117]

[0118] According to the test data of Table 1, it can be seen that when the zinc metal negative surface is introduced with a modification layer containing nitrogen-containing carbon material, the cycle life of the battery is significantly higher than that of the battery without the modification layer containing nitrogen-containing carbon material. Specifically, in Comparative Example 1, the modification layer of the negative electrode does not have nitrogen-containing carbon material, and the cycle life is 268 hours, while Comparative Example 2 without the modification layer of the negative electrode has a cycle life of only 106 hours. From Examples 1 to 15, it can be seen that the modification layer containing nitrogen-containing carbon material is introduced on the surface of the negative electrode, and the cycle life of the battery is between 360h and 450h.

[0119] The above has been described in detail. For those skilled in the art, without departing from the purpose and scope of the present application, and without unnecessary experiments, the present application can be implemented in a wider range under the same parameters, concentrations and conditions. Although the present application gives a special example, it should be understood that the present application can be further improved. In short, according to the principle of the present application, the present application is intended to include any change, use or improvement of the present application, including changes made by conventional techniques known in the art, which deviates from the scope disclosed in the present application.

Claims

1. Zinc metal negative electrode characterized in that, The zinc metal negative electrode substrate and a modification layer disposed on the surface of the zinc metal negative electrode substrate, the modification layer comprising nitrogen-containing carbon material; The modification layer with nitrogen-containing carbon material is grown in situ on the surface of the zinc metal negative electrode substrate; The root mean square roughness R q of the modification layer is 1.10 to 2.00, the arithmetic mean roughness R a is 1.20 to 1.80 A; The nitrogen-containing carbon material comprises graphite nitrogen, pyridine nitrogen and pyrrole nitrogen; The molar ratio of the graphite nitrogen, the pyridine nitrogen and the pyrrole nitrogen in the modification layer is (35-65):(15-40):(20-30); The method for preparing the zinc metal negative electrode comprises the following steps: 1) Place the zinc sheet in a plasma enhanced chemical vapor deposition system, and control the vacuum degree of the system in a first gas pressure range; 2) Introduce carbon-containing gas, maintain the vacuum degree of the system in a second gas pressure range, turn on the plasma system, set a first output power and adjust the circuit reflected power to a first value, run for a first time, then turn off the plasma system and stop introducing the carbon-containing gas; 3) Introduce nitrogen-containing gas and H2, maintain the vacuum degree of the system in a third gas pressure range, turn on the plasma system, set a second output power and adjust the circuit reflected power to a second value, run for a second time, then turn off the PECVD system, stop introducing the nitrogen-containing gas and H2, and obtain a zinc sheet coated with nitrogen-doped carbon, i.e. a zinc metal negative electrode; In step 1), the first gas pressure range is 1 x 10 -3 Pa or below; In step 2), the second gas pressure range is 0.1-10 Pa; In step 3), the third pressure range is 2 x 10 -1 ~ 2 x 10 Pa.

2. The zinc metal negative electrode of claim 1, wherein, The thickness H1 of the modification layer is 200 nm-2000 nm.

3. The zinc metal negative according to claim 1, wherein, The thickness H2 of the zinc metal negative electrode substrate is 0.5 mm-5 mm.

4. The zinc metal anode of claim 1, wherein, In the nitrogen-containing carbon material, the nitrogen atoms account for 0.3%-5% of all elements.

5. A secondary battery characterized by comprising: The secondary battery comprises the zinc metal negative electrode according to any one of claims 1-4.

6. An electric device, characterized by The secondary battery according to claim 5 is used as a power supply for the power-consuming device.

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